Method for fabricating semiconductor film and semiconductor device and laser processing apparatus

ABSTRACT

A technique to control segregation of impurities when reforming crystallinity and crystallization of a semiconductor film by using a laser beam irradiation is provided. The present invention is to irradiate the substrate with applying ultrasonic vibration while keeping the end portion of the substrate in space. The substrate on which a semiconductor film is formed is kept onto the stage provided with opening pores, and floated by spouting gas from opening pores. Supersonic vibration can be efficiently provided to the substrate by irradiating with a laser beam with ultrasonic vibration while keeping the end portion of the substrate.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for fabricating asemiconductor film having a crystal structure and a method forfabricating a semiconductor device using the semiconductor film.Specifically, the present invention relates to a technique to increasecrystallization and crystallinity by irradiating a semiconductor filmwith a laser beam. In addition, the present invention relates to a laserprocessing device which is used for the semiconductor film and thesemiconductor device.

[0003] 2. Description of the Related Art

[0004] A crystallization technique to form a polycrystalline silicon(polysilicon) by exposing an amorphous silicon film deposited on a glasssubstrate to a laser beam has been known. A pulsed excimer laseroscillator is a light source which is typically used for thecrystallization technique. It is considered that silicon isinstantaneously heated and melted due to the irradiation of a pulsedlaser beam, and crystallization is occurred in the subsequent coolingprocess. In consequence, it is known that polycrystallization in whichseveral crystal grains having different plane directions are collectedis formed.

[0005] In crystallization of amorphous silicon using an excimer laserwhich is typically used, a silicon is selectively heated throughirradiating with a pulsed laser beam with a pulse width of several tennanosecond to several hundred nanosecond, thereby the silicon iscrystallized without thermally damaging a glass substrate. Thecrystallization technique has attracted attention as a technique to forma semiconductor layer with a thin film transistor (TFT) which is usedfor a liquid crystal display device.

[0006] As shown in FIG. 5, a polysilicon film often used previously isformed by the following steps: forming a base insulating film 11 such assilicon nitride or silicon oxide over a glass substrate 10, irradiatingan amorphous silicon film with a thickness of 50 nm formed over the baseinsulating film with an excimer laser beam at a laser pulsed frequencyof 300 Hz (pulse width of 30 nsec), and then crystallizing the amorphoussilicon film. Still, projections having a shape like mountain chain suchas a projection 14 are formed onto the surface of the polysilicon film13.

[0007] In the case of forming a TFT, a gate insulating film with a filmthickness of approximately 100 nm is formed thereon. A decline ofwithstand pressure for an gate insulating film is caused due to thehigher concentration of electric field at the projection area and theincreased gate leak current. As the measure, there is a technique forpreventing projections due to the segregation of impurities fromgenerating onto the surface of the substrate by preventing thesegregation of impurities with applying ultrasonic vibration to thesubstrate during crystallization by means of exposing the film to alaser beam. (Reference 1, Japanese patent Laid-Open 11-204433)

[0008] As previous experimental knowledge, it is known that a largegrain size of crystallization is provided through crystallizing anamorphous silicon film in the atmosphere including oxygen by exposingthe film to a laser beam.

[0009] A pulsed excimer laser is condensed into a linear shape throughcrossing optical lens to scan an amorphous silicon film. Thus, the wholesurface of the amorphous silicon onto the glass substrate can becrystallized. However, the semiconductor film irradiated with the laserbeam becomes high temperature and a state of solvent, and then, reactswith oxygen and nitride in the atmosphere. The resulted substance getinto the film and the surface of the film, namely, exogenous impuritiesare mixed into the film and the surface of the film. Accordingly, theimpurities causes a crystal defect or become a factor of damaging aquality of the crystallization due to the segregated impurities in thegrain boundary.

[0010] Since these mixing of impurities occur unintentionally, thecrystallized semiconductor film processed with a laser beam includes alocal characteristic dispersion. Therefore, that becomes characteristicdispersion of a TFT formed by using the above semiconductor film, and aproblem that characteristic dispersion among plural TFTs elements in thesame substrate surface is caused.

[0011] In the above-described reference 1, it is described thatsegregation of impurities can be prevented and the occurrence of theprojections onto the surface of a substrate due to the segregation ofimpurities can be prevented by applying ultrasonic vibration to thesubstrate. However, in the case of using a method to connect aultrasonic vibration source with a stage on which a glass substrate ismounted, ultrasonic vibration source can not adhere to the stage becauseof a curve on the glass substrate, and ultrasonic vibration can notpropagate efficiently. The tendency becomes increasingly prominent asthe size of the glass substrate becomes bigger.

SUMMARY OF THE INVENTION

[0012] The present invention is proposed in view of the foregoingproblems. Hence, it is an object of the present invention to provide atechnique to control segregation of impurities during reforming thecrystallinity and the crystallization of a semiconductor film byirradiation of a laser beam.

[0013] The present inventors have examined the cause of dispersion incrystallinity about the semiconductor film which is crystallized byirradiation of a laser beam. The examination will be explained withreference to FIG. 4.

[0014] As shown in FIG. 4A, an amorphous silicon film 412 is formed overa substrate 410 through a base insulating film 411. The region which isirradiated with a pulsed laser beam 420 a is crystallized and acrystalline silicon film 413 is formed. At this moment, the amorphoussilicon film 412 is irradiated with pulsed laser beam 420 a in theatmosphere including oxygen such as in the air; a silicon film is heatedand becomes a state of solvent. As an example, in case that the pulsedlaser beam 420 a has the vibration frequency of 300 Hz and pulse widthof 30 nsec, the silicon is cooled and solidified by the time the siliconfilm is irradiated with the next pulsed laser beam. The crystallizationprogresses by the time the silicon is irradiated with the laser beam andsolidified, however, the silicon film becomes high temperature and anoxide 414(SiOx) can not be prevented from forming onto the silicon filmwhen processing in the air. (FIG. 4A)

[0015] Here, by irradiating with the next pulsed laser beam 420 b whileoverlapping the beam spot of the laser beam on the film, oxides 414having higher melting point than that of silicon becomes into pieces andare added into the melted silicon. (For example, 414 b shown in FIG.4B). When the oxides 414 b is segregated and concentrated into a grainboundary, dispersion in electric resistance is caused depending on thequantity or presence or absence of the oxides 414 b. Namely, aninfluence of barrier will be caused in the crystal grain boundary due tothe oxides 414 b.

[0016] When the film is irradiated with a laser beam in the atmosphereincluding nitride, it is expected that a piece of the nitride (SiNx) bealso mixed into the melted silicon and be segregated into a grainboundary.

[0017] Since an oxide and a nitride are electrical isolation, dispersionin electric conductivity of the silicon film is not small. In addition,pieces of the oxide melted in the silicon are mixed into the siliconfilm and work as an alleviation of lattice stress. In addition,favorable electrically properties can be obtained by carrying out laserirradiation in the atmosphere of oxygen compared with the case in theatmosphere of nitride since oxides do not become hindrance for takinghydrogen in the semiconductor film during hydrogenation process.

[0018] In the present invention, in the process for improving thecrystallization and the crystallinity of a semiconductor film which istypified by silicon, ultrasonic vibration is applied to the substrate orthe semiconductor film on the substrate to shatter and disperse thepieces of oxides and nitrides. Thus, segregation of oxides, nitrides orthe like can be prevented.

[0019] In the present invention, in a laser annealing technique forcrystallizing a amorphous semiconductor film formed over a substrate,improving crystallinity of polycrstal semiconductor film, orrecrystallizing after ion doping, a method for fabricating asemiconductor film comprises irradiating a semiconductor film formedover a substrate with a laser beam to crystallize the semiconductorfilm, wherein ultrasonic vibration is applied to the substrate duringirradiating the laser beam while holding an end portion of thesubstrate. Further, the method comprises holding a substrate over astage having pores wherein said substrate is provided with asemiconductor film, spouting gases from the pores to float thesubstrate, and irradiating a semiconductor film formed over thesubstrate with a laser beam while holding an end portion of thesubstrate, wherein during irradiating the laser beam, ultrasonicvibration is applied to the substrate. Thus, supersonic vibration can beefficiently provided to the substrate.

[0020] In the present invention, a semiconductor film comprising aamorphous structure is formed and crystallized using irradiation of alaser beam with ultrasonic vibration by a method for fabricating asemiconductor device including processes for crystallizing of amorphoussemiconductor film formed onto a substrate and improving crystallinityof a polycrystal semiconductor film.

[0021] A semiconductor film may be crystallized by irradiating with apulsed laser beam which is condensed into a linear shape with applyingultrasonic vibration while the substrate is floated. The pulsed laserbeam is used to crystallize the whole area of the semiconductor film bymoving the beam spot on the film to overlap each other. The laser beamcan be emitted in the air, in the inert atmosphere, in the reductionatmosphere, in the oxidizing atmosphere or under reduced pressure (or invacuum).

[0022] In addition, the present invention provides a laser processingapparatus comprising a means for floating and moving the substratehorizontally, an optical system for condensing a laser beam in arectangle or a linear shape, and a means for applying ultrasonicvibration to the substrate. Further, the laser processing apparatus canmove a substrate in horizontal direction by a means for moving thesubstrate in one direction while keeping the end portion of thesubstrate and a means for floating the substrate in space. Further, thelaser processing apparatus comprises an optical system to irradiate thesubstrate with a laser beam, and a means for applying ultrasonicvibration to the substrate from a region of keeping the substrate.

[0023] The energy of the ultrasonic vibration can be utilized to shatterand disperse the pieces of oxides and nitrides formed on the surface dueto the irradiation of the laser beam. The vibration frequency is equalto or more than 100 kHz and equal to or less than 30 MHz. The effect ofthe ultrasonic vibration depends on the vibration frequencies, and it ispreferable to set vibration frequency of equal to or more than 100 kHzand equal to or less than 2 MHz to finely chatter the pieces of oxidesand nitrides. Also, it is more preferable to set the vibrationsfrequency of equal to or more than 1 MHz and less than 30 MHz toeliminate projections onto the surface of the semiconductor film.

[0024] Namely, as a model shown in FIG. 3, a crystalline silicon film413 is formed by irradiating an amorphous silicon film 412 onto a baseinsulating film 411 formed on a substrate 410 with a pulsed laser beam420 a while being added with ultrasonic vibration. In the process, anoxide 414(SiOx) is formed onto the surface of the semiconductor film;however, the oxide is shattered into pieces (FIG. 3A). Further, afterthe irradiation of the pulsed laser beam 420 b, the oxide 414 can beprevented from segregating into the particular region of crystallinesilicon film 413 (FIG. 3B). Therefore, pieces of oxide can be preventedfrom concentrating in a grain boundary, and thus dispersion in electricresistance can be reduced.

[0025] To prevent oxides and nitrides from generating on the surface ofthe semiconductor film due to the irradiation of the laser beam, it canbe carried out in the rare atmosphere, in the reduction atmosphere, orin vacuum.

[0026] As described above, the present invention is to performcrystallization without segregating impurities by using a laser beamirradiation while applying ultrasonic vibration to a substrate on whichamorphous semiconductor film is formed. Further, the present inventioncan be applied to the crystallization of a semiconductor film using acatalytic element. Namely, a metallic element or a metallic compoundwhich have catalytic action to promote crystallization is added to theamorphous semiconductor film formed on the substrate and subsequentlythe film is irradiated by a laser beam while applying ultrasonicvibration after crystallizing a part of or whole area of thesemiconductor film by heat treatment. Thus, the film can be crystallizedwithout segregating impurities, the metallic element or the metalliccompound being mixed unintentionally in the specific regions.

[0027] In addition, an amorphous semiconductor film in this invention isnot limited to the one which has a complete amorphous structure in astrict sense, but includes the one which comprises a state having aminute crystal grain, so-called a microcrystalline semiconductor film,or a semiconductor film locally having a crystal structure. Besides, anamorphous silicon film which is typically used, an amorphous silicongermanium film and an amorphous silicon carbide film can be applied tothe amorphous semiconductor film.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a diagram showing a mode of the laser processingapparatus according to the present invention;

[0029]FIGS. 2A and 2B are diagrams showing a stage section of the laserprocessing apparatus, and a conveyor means according to the presentinvention is detail;

[0030]FIGS. 3A and 3B are diagrams showing a model of segregation ofimpurities during the process of a laser beam irradiation;

[0031]FIGS. 4A and 4B are diagrams showing a model in which segregationof impurities can be prevented during the process of a laser beamirradiation;

[0032]FIG. 5 is a diagram showing a polycrystalline semiconductor filmformed by conventional laser annealing.

[0033]FIG. 6 is a diagram showing a mode of the laser processingapparatus according to the present invention;

[0034]FIG. 7 is a diagram showing a stage section of the laserprocessing apparatus, and a conveyor means according to the presentinvention is detail;

[0035]FIGS. 8A to 8C are diagrams showing a method for fabricating asemiconductor device according to the present invention;

[0036]FIG. 9 is a diagram showing a method for fabricating asemiconductor device according to the present invention;

[0037]FIGS. 10A to 10C are diagrams showing a method for fabricating asemiconductor device according to the present invention;

[0038]FIGS. 11A to 11E are diagrams showing a method for fabricating asemiconductor device according to the present invention;

[0039]FIGS. 12A and 12B are diagrams showing a method for fabricating asemiconductor device according to the present invention;

[0040]FIG. 13 is a diagram showing a structure of an integrated circuitaccording to the present invention;

[0041]FIGS. 14A and 14B are diagrams showing a stage section of thelaser processing apparatus, and a structure for applying ultrasonicvibration in detail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The embodiment mode of the present invention is described indetailed with reference to drawings. However, it is easily understood bythose skilled in the art that the present invention is not limited tothe following description and can be freely changed the modes and thedetails without any departure from the purpose and the scope of theinvention. Therefore, the invention should not be limited to interpretto the description of the following embodiment modes.

Embodiment Mode 1

[0043]FIG. 1 is a diagram showing one mode of a laser processingapparatus according to the present invention. And the apparatuscomprises a laser oscillator 101, an optical system 102, a stage 103, asubstrate floating means 104, a transporting means 105 for pinching andmoving the substrate, and an ultrasonic vibration source 106 forapplying ultrasonic vibration to the chuck 107.

[0044] A laser beam irradiated from a laser oscillator 101 is condensedand extended to form a shape of beam spot into a fine linear shape bythe optical system 102. A structure of the optical system 102 isproperly decided, however, the optical system 102 comprises, forexample, a cylindrical lens array 110, a cylindrical lens 111, a mirror112, a doublet cylindrical lens 113, and the like. Though it depends tothe size of the lens, it is possible to irradiate a linear laser beamhaving approximately from 100 to 400 mm (length) in the longitudinaldirection and approximately from 100 to 500 um(length) in the lateraldirection.

[0045] Moreover, a gas supply means 108 and a nozzle 109 may be providedfor the purpose of controlling the atmosphere around a laser beamirradiation section. It is possible to control the atmosphere withoutproviding any particular chamber by replacing atmosphere around thelaser beam irradiation section with the gas spouted from the nozzle 109.The supply of oxidizing gas, reducing gas, and inert gas from the gassupply means 108 is possible. By the selection of the gas, oxide can betaken into the semiconductor film actively, or rare gas such as argon(Ar) can be taken thereinto.

[0046] Furthermore, a structure in which heated gas is to be spoutedfrom the nozzle 109 may be adopted by adding a heating means to themeans for controlling the atmosphere. As a result, a formed substancesuch as a substrate in the end portion of a laser beam irradiationsection or a semiconductor film over the substrate can be heated. And ittakes a long time to melt a semiconductor film which is irradiated by alaser beam, then a planarization effect can be achieved even ifultrasonic vibration frequency applied to the substrate is equal to orless than 1 MHz.

[0047] Needless to say, irradiation of a laser beam in the air, orirradiation of a laser beam under reduced pressure (or in vacuum) whilekeeping a stage 103 in the chamber can be performed without providing aspecial means described above.

[0048] A gas laser such as an excimer laser which oscillates lighthaving a wavelength of 400 nm or smaller, or a solid-state laser such asa YAG, a YVO₄ or a YLF laser are used as the laser. A basic wave (1064nm), a second harmonic (532 nm), a third harmonic (354.7 nm) or the likecan be used in the YAG and the YVO₄ laser into which Cr, Nd, Er, Ho, Ce,Co, Ti, or Tm is doped. Concerning the lasers, a pulsed laser is usedand an oscillation frequency of approximately from 5 to 300 Hz isadopted.

[0049] The substrate floating means 104 is provided with the stage 103.A substrate 114 is floated over the stage 103 by providing with openingpores for spouting and absorbing gas, and controlling respective flowvolume or flow rate. The substrate floating means 104 and the endportion of the substrate are pinched to combine with the transportingmeans 105 which moves the substrate to the uniaxial direction or thebiaxial direction. Thus, a structure in which a conveyor means toconveyor the substrate 114 kept floating in the space can be attained.An irradiation of a laser beam condensed in a rectangle or a linearshape can be performed on the entire surface of the substrate. Further,ultrasonic vibration supplied from ultrasonic vibration source 106 isprovided with the chuck section 107 in the transporting means 105,subsequently, thereby the propagating the vibration efficiently to thesubstrate. Alternatively, a structure in which the substrate 114 isfixed with pinching by the chuck 107 and the laser beam is scanned by apolarization means such as a galvanometer mirror may be employed.

[0050] This type of laser irradiation apparatus is particularlyeffective in the case of processing a glass substrate with a length ofone side more than 1000 mm and a thickness equal to or less than 1 mm.For example, a glass substrate which has a size of 1200 mm×1600 mm or2000 mm×2500 mm and has a thickness of 0.4 to 0.7 mm can be processed. Aglass substrate easily curves if the surface area of the glass substrateis large-sized and the thickness thereof becomes small. However, thesubstrate can be kept with maintaining a level surface by holding thesubstrate using the gas spouted from the fine pores as described in astructure of a stage 103. Further, the glass substrate does not contactwith any subject except the transporting means 105 which provide withultrasonic vibration, thus, ultrasonic vibration can be efficientlyapplied to the glass substrate without diminishing the ultrasonicvibration.

[0051] The condition of the crystallization can be properly selected byselecting the gas blown from the nozzle 109 from among oxidizing gas,reducing gas, or inert gas in the laser irradiation apparatus. Astructure of this type of laser irradiation apparatus does not need achamber which controls the atmosphere during the irradiation of a laserbeam, therefore, even if the substrate becomes a large size, small sizedirradiation apparatus can be achieved.

[0052]FIGS. 2A and 2B are diagrams showing the end portion of the stage103 in detail. The substrate 114 over the stage 103 is floated by thesubstrate floating means 104 and is pinched by the chuck 107. Thefloating height of the substrate is adjusted by spouting and absorbinggas from opening pores provided for the stage 103 at the same time inthe substrate floating means 104. Supersonic vibration is to be appliedto the chuck 107 from the ultrasonic vibration 106.

[0053] As the substrate 114, for example, a commercially producedno-alkali glass substrate can be used. The thickness of the substrate isnot limited, however, it is preferably to use a substrate having athickness of approximately 0.2 to 2 mm. A base insulating film 115formed of silicon nitride, silicon oxide, or the like is formed over thesubstrate 114, and a semiconductor film 116 with a thickness of 20 to200 nm is formed thereon. The semiconductor film 116 may be an amorphoussemiconductor film or a crystalline semiconductor film which is alreadycrystallized by heat treatment or the like. Moreover, the structureshown in FIG. 2 is a structure in which the substrate 114 is pinched attwo points using the chuck section 107, the present invention is notlimited hereto, and a structure in which the substrate is pinched atplural points while being contacted with ultrasonic vibration source inplural points may be employed. Furthermore, the substrate can be fixedas an end side of the substrate are held down.

[0054] As shown in FIG. 2, the substrate is irradiated with a laser beam117 overlapped each other as laser beams a to c by pulsed oscillation.Namely, the pulsed laser beams on the film are overlapped each other at10 to 99 percent, preferably 80 to 98 percent.

[0055] As described in this embodiment, ultrasonic vibration can beapplied with the substrate sufficiently by floating the substrate inspace, and adding ultrasonic vibration from the end portion of thesubstrate. Consequently, the film can be crystallized withoutsegregating impurities being mixed into a semiconductor filmspontaneously to the specific region.

Embodiment Mode 2

[0056] In this embodiment mode, a mode of the laser processing apparatusin which the irradiated regions are overlapped with one another by usingplural laser beams is explained using FIG. 6 and FIG. 7. In the laserprocessing apparatus of the present embodiment mode, the second harmonicof a solid-state laser is shaped and the laser beam in which shape ofthe laser spot is to be an oblong or a rectangle is scanned by using apolarization means of galvanometer mirror or the like, and the laserbeam of fundamental wave is overlapped to the beam spot of secondharmonic so as to provide more energy at the same time.

[0057] In FIG. 7, a solid-state laser oscillator for a laser diode type(LD) is preferably used as a first laser oscillator 121. For example,Nd:YVO₄ laser oscillator, continuous-wave laser (CW), or the secondharmonic (532 nm) can be used. Preferably, the Nd: YVO₄ laser oscillatorhas an oscillation mode of TEM₀₀, LBO crystallization is incorporated inthe resonator, and that of laser oscillator is changed to the secondharmonic. The diameter of a beam is to be 2.25 mm, and the beamdivergence is to be approximately 0.3 mrad.

[0058] An optical system 122 condenses laser beams in an oblong or arectangle shape. For instance, since the beam spot of a laser beam whichis outputted in an oscillation mode of TEM₀₀ have a cross section of around shape, the optical system which transform the shapes describedabove into an oblong shape is to be a beam expander made of two piecesof cylindrical lens, in which the beam can be expanded only in onedirection. In addition, the regular beam expander can be combined andused with the beam expander so that beam divergence may be controlled.

[0059] A laser beam which is transformed into an oblong shape isdeflected by a deflection means 123. As the deflection means 123, areflector such as a galvanometer mirror or a polygon mirror can beapplied. The substrate 114 is irradiated with the deflected laser beamthrough a fθ lens 124. The first laser beam 125 transformed into anoblong shape is condensed onto the substrate 114 by the fθ lens 124, andthus, oblong beam, for example, having 20 um of minor axis and 400 um ofmajor axis can be shaped.

[0060] The first laser beam 125 is scanned by changing the deflectionangle of the deflection means 123. The change of a beam spot shape inthe first laser beam 125 due to the angle of the deflection mean 123 canbe controlled by the fθ lens 124. The incident angle of the first laserbeam 125 against the main surface of the substrate 114 is set at 20degrees. The occurrence of the interference with incident light from thefirst laser beam 125 and reflectance light from the backside of thesubstrate can be prevented. In the present embodiment mode, thedeflection means 123 is scanned only in the uniaxial direction using apiece of galvanometer mirror. The substrate 114 is moved to the crosseddirection toward uniaxial direction by a conveyor means for fullyscanning the whole two-dimensional plane. The scanning speed of thefirst laser beam 125 is set to 100 to 2000 mm/s, preferablyapproximately, 500 mm/s.

[0061] A second laser oscillator 128 may be provided to irradiate thesubstrate 114 by the second laser beam 131 having fundamental wave (1064nm) in accordance with the first laser beam 125 having the secondharmonic (532 nm). As the second laser oscillator 128, a Nd:YAG laseroscillator of LD excitation is used. The second laser beam 131 is formedby, for example, enlarging the beam uniformly by a concave lens 129 andcondensing the beam into one direction using a plane-convex cylindricallens 130. Also, the similar beam can be formed by using an opticalsystem having other structure. A homogenizer may be used in order toequalize the energy distribution of the second laser beam 131, then, thedesign of the homogenizer has to be performed in view of theinterference of the laser beam. For example, a method of equalizing theenergy distribution by dividing and combining laser beams is used in thehomogenizer, in this case, a measure for making the optical pathdifferenct that is equal to or longer than the coherent length of thelaser beam to each the divided laser beams is required to prevent theoccurrence of interference.

[0062] A substrate floating means 104 is provided with a stage 103. Themeans 104, and a transporting means 105 for pinching the end of thesubstrate and moving the substrate unidirectionally or bidirectionallyare combined. Thus, a conveyor means to conveyor the thin substrate canbe formed while keeping the substrate in the space. The oscillationsupplied from a ultrasonic vibration source 106 is provided with thechuck section 107 of the transporting means 105, and thus, theoscillation can be efficiently propagated through the substrate.

[0063]FIG. 6 is a diagram showing the end portion of the stage 103 indetail. It shows a mode of crystallizing an amorphous silicon film 116formed onto the substrate 114. The substrate 114 is floated by thesubstrate floating means, and pinched by a chuck 107 of the transportingmeans 105. The chuck 107 is to be provided with ultrasonic vibrationfrom the ultrasonic vibration source 106.

[0064] The second laser beam 131 is expanded to the scanning directionof the first laser beam 125 which is scanned by a deflection means.Preferable, the first laser beam 125 is to fully cover the region whichis scanned in uniaxial direction and irradiated.

[0065] The fundamental wave of Nd:YAG laser with an oscillationwavelength of 1064 nm is small because the absorption coefficient of thesilicon is not more than 10⁴/cm, however, the absorption coefficient ofthe fundamental wave is increased by irradiating the film by the secondharmonic and the fundamental wave at the same time and dissolving thefilm thereof. Namely, crystallization is easily occurred using thefundamental wave by utilizing the rise of absorption coefficient inaccordance with the liquefaction of the silicon. The effect thereof isthat the sudden temperature change of the silicon film can be controlledand the energy of the second harmonic with small output can be assistedto make the crystallization easy. Unlike the higher harmonic, it is notnecessary for the fundamental wave to use a nonlinear optical elementfor converting a wavelength, and it is possible to obtain a laser beamwith a quite large output. For example, energy more than centuple ofthat of the higher harmonic can be obtained. Since the proof strength ofthe nonlinear optical element against the laser is quite weak, suchenergy difference is caused. In addition, the nonlinear optical elementfor generating the higher harmonic is likely to change in quality, andthere are disadvantages in that a maintenance-free state that is anadvantage of solid-state laser can not maintain for a long time, forinstance.

[0066] According to the present embodiment mode, in the case where amelting zone is provided to a semiconductor film and the semiconductorfilm is scanned in succession for the crystallization, crystalizaitonwithout segregating impurities being mixed unintentionally into thespecific regions is made possible and a crystalline semiconductor filmwithout segregating impurities can be obtained, simultaneously.

Embodiment Mode 3

[0067] In this embodiment mode, a structure of a laser irradiationapparatus provided with a function which is to provide ultrasonicvibration to a substrate through solvent is explained with reference toFIG. 14.

[0068]FIG. 14A is a diagram shown the top view of the substrate 114 thatis irradiated by a laser beam 153, and guide rails 150 are provided withboth ends of the substrate 114. Ultrasonic transducers 151 are providedwith the guide rails 150, and thereby ultrasonic vibration is applied tothe substrate 114. Namely, as shown in FIG. 14B, a solvent 152 is put inthe guide rails 150, ultrasonic vibration is propagated to the substratethrough the solvent 152. The solvent 152 may be a liquid solvent orjelled solvent, and impedance in the solvent is preferably close to thatin the substrate, to be simplified, water can be used instead. Asdescribed above, ultrasonic vibration can be efficiently applied to thesubstrate 114 by contacting between ultrasonic transducer and liquidthrough a guide rail. In addition, the substrate 114 may be kept floatedby the substrate floating means 104 provided to the stage 103.

[0069] As the substrate 114, for example, a commercially producedno-alkali glass substrate can be used, however, the film thickness isnot limited, preferably, approximately, 0.2 to 2 mm. A base insulatingfilm 115 is formed on the substrate 114, and a semiconductor film 116with a thickness of 20 to 200 is formed thereon. The substrate 114 isheld and fixed between the guide rails 150; a laser beam 153 may bemoved over the substrate by a deflection means, or the substrate can beheld by the chuck 107 and moved along the guide rails 150 while keepingthe beam spot on the film of the laser beam 153 constant.

[0070] The laser beam 153 can be a pulsed laser beam, or acontinuous-wave or continuous emission laser beam, and the types are notlimited. Specifically, an optical system for laser irradiation in alaser processing apparatus of the present embodiment mode is notspecifically limited, provided that the desired laser processing such ascrystallization for the semiconductor film is possible. For example, thelaser processing apparatus may include optical systems shown inEmbodiment Mode 1 and/or Embodiment Mode 2 or the like.

[0071] According to the present embodiment mode, ultrasonic vibrationcan be easily applied to the direction parallel to the horizontal planeof the substrate 114. Thus, the film can be crystallized withoutsegregating impurities being mixed unintentionally into a semiconductorfilm to the specific regions, and simultaneously, segregation ofimpurities and projections onto the surface of the semiconductor filmdue to the laser irradiation can be prevented from occurring.

Embodiment Mode 4

[0072] In the present invention, crystallization without segregatingimpurities is made possible by irradiating the substrate on which anamorphous semiconductor film is formed with a laser beam whileultrasonic vibration is applied. However, the invention is not limitedhereto, and can be applied to the crystallization of the semiconductorfilm using a catalytic element.

[0073] First, as shown in FIG. 8A, a base insulating film 202 which iscomposed of an insulating film such as a silicon oxide film, a siliconnitride film, or a silicon oxynitride film, is formed on a substrate201. Specifically, reactive gas of SiH₄, NH₃, and N₂O is used to form afirst silicon oxynitride film containing nitrogen more than or nearlyequal to oxygen with plasma CVD at a substrate heating temperature of400° C. and reactive gas of SiH₄ and N₂O is used to form a secondsilicon oxynitride film containing oxygen more than nitrogen with plasmaCVD at a substrate heating temperature of 400° C., to form the baseinsulating film 202 from the first and second silicon oxynitride filmswith a laminated structure.

[0074] In the laminated structure, the first oxynitride film may besubstituted with a silicon nitride film formed with high-frequencysputtering. The silicon nitride film can prevent diffusion of a smallamount of alkali metal such as sodium (Na) included in a glasssubstrate.

[0075] A semiconductor layer for forming channel, source, and drainportions of a TFT is obtained by crystallizing an amorphous silicon film203 formed on the base insulating film 202. An amorphous silicon filmformed with plasma CVD at a substrate heating temperature of 300° C. hasa thickness from 20 to 60 nm. For the semiconductor layer, an amorphoussilicon-germanium (Si_(1-x)Gex; x=0.001 to 0.05) film may be appliedinstead of the amorphous silicon film.

[0076] In order to perform crystallization, a metal element such asnickel (Ni), which has a catalytic action to crystallization of asemiconductor, is added. In FIG. 8A, heat treatment due to radiationheating or conduction heating is performed for crystallization after aplatinum (Pt) containing layer 204 is kept on the amorphous silicon film203. For example, RTA (Rapid Thermal Anneal) with radiation of a lamp asa heat source or RTA (gas RTA) with heated gas is performed at a heatingtemperature 740° C. for 180 seconds. The heating temperature is atemperature of a substrate measured with a pyrometer, and thetemperature shall be a set temperature at heat treatment. Alternatively,heat treatment at 550° C. for 4 hours may be performed with an annealingfurnace. The crystallizing temperature is lowered and time forcrystallization is shortened due to the action of the metal element withthe catalytic action.

[0077] In order to further improve the crystallinity of thus formedcrystalline silicon film 205, laser processing is performed (FIG. 8B).The laser processing can be performed by using the laser processingapparatus in the Embodiment Mode 1, Embodiment Mode 2, or EmbodimentMode 3. Namely, the substrate 201 is pinched in the chuck 107, providedwith the ultrasonic vibration from ultrasonic vibration source 106, andirradiated with a laser beam 206 with pulsed oscillation or continuousoscillation. The laser beam 206 can be a pulsed excimer laser beam asshown in FIG. 1, a continuous-wave laser beam as shown in FIG. 7, or acontinuous emission excimer laser beam.

[0078] Owing to the irradiation of the laser beam 206, crystallinity canbe improved; such as to increase the crystallization rate by eliminatingan amorphous region. At the same time, a metal element which is left ina crystalline silicon film 205 can be dispersed. Thus, a crystallinesilicon film 207 can be obtained. (FIG. 8C)

[0079] In order to remove impurities such as metal included in acrystalline silicon film, gettering shown in FIG. 9 is performed, whichis especially effective for reducing platinum (Pt) to a concentration of1×10¹⁷/cm³ or less. In FIG. 9, as a gettering site, an amorphous siliconfilm 209 is formed over the crystalline silicon film 207 with a barrierlayer 208 therebetween. The amorphous silicon film 209 includes animpurity element such as phosphorous or boron, a rare gas element suchas Ar, Kr, or Xe, or an element such as oxygen or nitrogen at 1×10²⁰/cm³or more to form a distortion. It is preferred that high-frequencysputtering is performed with Ar as sputtering gas to form the amorphoussilicon film.

[0080] As heat treatment, RTA with a lamp as a heat source or RTA (gasRTA) with heated gas is performed at 750° C. for 180 seconds.Alternatively, heat treatment at 550° C. for 4 hours is performed withan annealing furnace. A metal element used for a catalyst is dispersedby a laser beam irradiation with added ultrasonic vibration, and thus,the metal element can be easily eliminated by the heat treatment. Withthe heat treatment, the metal element is segregated to the side of theamorphous silicon film 209, resulting in improving the purity of thesemiconductor film 207. After the heat treatment, the amorphous siliconfilm 209 is removed with dry etching that uses NF₃ or CF₄, dry etchingthat does not use plasma of ClF₃, or wet etching using an alkalisolution such as solution including hydrazine or tetra ethyl ammoniumhydro oxide ((CH₃)₄NOH). The barrier layer 208 is removed withhydrofluoric acid etching.

[0081] Thus, a crystalline semiconductor film can be obtained. However,the condition for crystallization and gettering which is described inFIGS. 8 and 9 is an example, the operator can properly decide the heattreatment temperature or the laser processing condition.

Embodiment Mode 5

[0082] In the present embodiment mode, fabricating processes of asemiconductor device will be described, which includes a processingstage to adding laser annealing to a portion with a laminate structureof a semiconductor film, a gate insulating film, and a conductive film.

[0083] First, etching a semiconductor film formed on a substrate into adesired shape in accordance with Embodiment Mode 4 for dividing thesemiconductor film into an island-shape, thus, the semiconductor film213 shown in FIG. 10A is obtained. In this way, a semiconductor film 213is formed to be a main part of a TFT for a channel region and source anddrain regions. As a substrate 201, a substrate such as a commerciallyproduced no-alkali glass substrate can be used, and a base insulatingfilm 202 including silicon nitride, silicon oxide, or silicon oxynitrideis formed between the substrate and the semiconductor film with athickness of 50 to 200 nm. Further, to the semiconductor film 213,doping of an impurity element for imparting a p-type is performed inorder to shift threshold voltage to a plus side, or doping of animpurity element for imparting an n-type is performed in order to shiftthreshold voltage to a minus side.

[0084] Next, plural insulating films for the gate insulating film 214are deposited on the semiconductor film 213 with a thickness of 10 to120 nm. The gate insulating film 214 can be formed by a silicon oxidefilm, a silicon nitride film or a complex of those lamination films byusing plasma CVD or high-frequency sputtering. When the gate insulatingfilm is formed by sputtering, single crystal silicon is used for atarget, and oxygen or nitrogen is used for sputtering gas. Sputtering isperformed by inducing glow discharge through applying high frequencypower of 1 to 120 MHz.

[0085] The gate insulating film 214 is to be laminated structure of, forexample, silicon oxide film having 10 to 60 nm in thick and siliconnitride film having 10 to 30 nm in thick. Since, in the gate insulatingfilm with the laminated structure, silicon nitride has a relativedielectric constant of about 7.5 with respect to a relative dielectricconstant 3.8 of silicon oxide, it is possible to obtain an effect thatis substantially equivalent to the case of obtaining a thinnedinsulating film.

[0086] With regard to the smoothness of the surface of the semiconductorfilm 213, a concave-convex shape can be a maximal value of 10 nm orless, preferably 5 nm or less by applying the ultrasonic vibrationduring the irradiation of a laser beam. Here, if the gate insulatingfilm has a two-layer structure of the silicon oxide film and the siliconnitride film, it becomes possible to reduce gate leakage current anddrive a TFT at 2.5 to 10 V, typically at 3.0 to 5.5 V, even if the gateinsulating film has a total thickness from 30 to 80 nm.

[0087] After forming the gate insulating film 214, a first conductivefilm 215 is formed. A material of the first conductive film 215 isselected from high melting point metal such as molybdenum (Mo), tungsten(W), and titanium (Ti), metal nitride such as titanium nitride, tantalumnitride, and tungsten nitride, silicide such as tungsten silicide(WSi₂), molybdenum silicide (MoSi₂), titanium silicide (TiSi₂), tantalumsilicide (TaSi₂), chromium silicide (CrSi₂), cobalt silicide (CoSi₂),and platinum silicide (PtSi₂), polysilicon to which phosphorous or boronis doped, and the like. The first conductive film 215 has a thicknessfrom 10 to 100 nm, preferably from 20 to 50 nm.

[0088] Then, as shown in FIG. 10B, irradiation of electromagnetic wave216 from heat source is performed to the first conductive film 215 byRTA or flash lamp anneal in order to heat the conductive film.Temperature becomes high in the region in which the first conductivefilm 215 is formed, thus, local heat treatment becomes possible. Withthis local treatment, it is possible to oxidize or nitride a minutesilicon cluster included in the film and to relax the inner distortionto reduce a defect density in the film and an interface defect statedensity.

[0089] After that, as shown in FIG. 10C, an element selected formtantalum (Ta), tungsten (W), titanium (Ti), molybdenum (Mo), aluminum(Al), and copper (Cu), or an alloy or a compound containing the metalelement above as its main component is deposited as a second conductivefilm 217. A gate electrode is formed by processing the first and secondconductive films 215 and 217, and preferably, that the first conductivefilm 215 formed of a tantalum nitride (TaN) film is combined with thesecond conductive film 217 formed of a tungsten (W) film, or the firstconductive film 215 formed of a tantalum nitride (TaN) film is combinedwith the second conductive film 217 formed of a titanium (Ti) film.

[0090] As shown in FIG. 11A, a second conductive layer 218 being etchingprocessed by matching the pattern of the gate electrode is formed on thefirst conductive film 215. Then, impurities of one type of conductivityare doped into the semiconductor film using the second conductive layer218 as a mask. The conductive type impurities are doped into thesemiconductor film 213 through the first conductive film 215 andconsequently, a first impurity region 219 is formed. (FIG. 11B)

[0091] Then, an insulating film of such as silicon oxide film is formedonto the first conductive film 215 and the second conductive film 218,then, a side spacer 220 is formed by anisotropic etching. (FIG. 11C) Asecond impurity region 221 doped one type of conductivity impuritiesthrough the first conductive layer 215 is formed in self-aligning mannerusing the sides pacer 220 and the second conductive layer 218 as a maskduring the doping process. (FIG. 11D)

[0092] As impurities of the one type of conductivity, an element such asphosphorous or arsenic, belonging to Group 15 in the periodic table, isused in the case of an n-type impurity (donor), and an element such asboron, belonging to Group 13 in the periodic table, is used in the caseof a p-type impurity (acceptor). When the impurities are selectedappropriately, it is possible to fabricate an n-channel TFT or ap-channel TFT. Further, it is possible to form an n-channel TFT and ap-channel TFT both on the same substrate only by adding a mask patternfor doping.

[0093] In order to activate the second impurity region 221 formed for asource and a drain and the first impurity region 219 formed for an LDD,irradiation of the laser beam 222 is performed to the semiconductorlayer 213. Any one of laser processing apparatuses shown in theEmbodiment Mode 1 to 3 can be used when irradiation of the laser beam222 is performed.

[0094] Further, the first conductive layer 215 is etched using thesecond conductive layer 218 and the side spacer 220 as a mask. Then,mixed gas of SiH₄, N₂O, NH₃, and H₂ is used to form a silicon oxynitridefilm including hydrogen as a third insulating layer 223 with plasma CVDat a substrate heating temperature of 250 to 350° C., which has a filmthickness from 50 to 200 nm. After that, heat treatment at 410° C. in anitrogen atmosphere is performed for hydrogenation of the semiconductorlayer. (FIG. 12A)

[0095] After that, a photosensitive or nonphotosensitive organic resinmaterial containing a material such as acrylic or polyimide as its maincomponent is used to form a fifth insulating layer 224. A wiring 225formed of a conductive material such as Al, Ti, Mo or W is appropriatelyprovided with the contact hole formed in the third to fifth insulatinglayers. When the organic resin material is used to form the fifthinsulating film, capacitance between wirings is reduced and the surfacehas smoothness. Therefore, it is possible to realize providing wiringson the fifth insulating layer with high density. (FIG. 12B)

[0096] Thus, a TFT having a gate overlap LDD (Low concentration drain)structure can be completed. According to the present embodiment, a TFTin which influence of characteristic dispersion due to segregation ofimpurities is removed can be obtained.

Embodiment Mode 6

[0097] An embodiment mode of a microcomputer will be described as arepresentative semiconductor device fabricated according to EmbodimentModes 5 with reference to FIG. 13. As shown in FIG. 13, a microcomputerintegrataed various functional circuit sections on a glass substratewith a thickness of 0.3 to 1.1 mm can be realized. It is possible toform the various functional circuit sections with a integrated circuitfabricated in a TFT of the present Embodiment Mode 5.

[0098] Elements of a microcomputer 300 shown in FIG. 13 include a CPU301, a ROM 302, an interrupt controller 303, a cache memory 304, a RAM305, a DMAC 306, a clock generation circuit 307, a serial interface 308,a power supply generation circuit 309, an ADC/DAC 310, a timer counter311, a WDT 312, an I/O port 302, and the like.

[0099] In this embodiment mode, a mode of a microcomputer is describedas an example. However, semiconductor devices with various functionssuch as a media processor, a graphics LSI, an encryption LSI, a memory,and an LSI for cellular phones can be completed by changing structuresand combinations of various functional circuits.

[0100] In addition, it is possible to fabricate a liquid crystal displaydevice or an EL (electroluminescence) display device with using a TFTformed on a glass substrate. As electronic devices each using suchdisplay devices, a video camera, a digital camera, a goggles-typedisplay (head mount display), a navigation system, a sound reproductiondevice (such as an in-car audio system and an audio set), a lap-toppersonal computer, a game machine, a portable information terminal (suchas a mobile computer, a cellular phone, a portable game machine, and anelectronic book), an image reproduction device including a recordingmedium (more specifically, an device which can reproduce a recordingmedium such as a digital versatile disc (DVD) and display the reproducedimage), and the like can be given. Further, it is also possible to applythe liquid crystal display device or the EL display device as a displaydevice incorporated in an electric home appliance such as arefrigerator, a washing machine, a microwave, a telephone, a facsimile,a vacuum sweeper, a thermos bottle, or rice cooker. As set forth above,the present invention can be applied quite widely to products in variousfields.

[0101] According to the present invention, segregation of impurities canbe prevented by applying ultrasonic vibration to the substrate withholding the end portion when reforming crystallinity and crystallizationof a semiconductor device by using a laser beam irradiation. The energyof the ultrasonic vibration can be utilized to shatter and disperse thepieces of oxides and nitrides formed on the surface by a laser beamirradiation. Therefore, pieces of oxides can be prevented fromconcentrating in a grain boundary, and thus dispersion in electricresistance can be reduced.

[0102] In addition, a metal element left in the crystallinesemiconductor film can be dispersed by applying the present invention tocrystallize a semiconductor film using a catalytic element. Accordingly,thereafter, gettering can be easily performed.

What is claimed is:
 1. A method for fabricating a semiconductor filmcomprising: irradiating a semiconductor film formed over a substratewith a laser beam to crystallize the semiconductor film, whereinultrasonic vibration is applied to the substrate during irradiating thelaser beam while holding an end portion of the substrate.
 2. A methodfor fabricating a semiconductor film according to claim 1, wherein saidlaser beam is a YVO₄, a YAG, a YLF or an excimer laser.
 3. A method forfabricating a semiconductor film comprising: holding a substrate over astage having pores wherein said substrate is provided with asemiconductor film; spouting gases from the pores to float thesubstrate; and irradiating a semiconductor film formed over thesubstrate with a laser beam while holding an end portion of thesubstrate, wherein during irradiating the laser beam, ultrasonicvibration is applied to the substrate.
 4. A method for fabricating asemiconductor film according to claim 3, wherein said laser beam is aYVO₄, a YAG; a YLF or an excimer laser.
 5. A method for fabricating asemiconductor device comprising: forming a semiconductor film having anamorphous structure over a substrate; and irradiating the semiconductorfilm with a laser beam while applying ultrasonic vibration to thesubstrate to crystallize the semiconductor film.
 6. A method forfabricating a semiconductor device according to claim 5, wherein saidlaser beam is a YVO₄, a YAG, a YLF or an excimer laser.
 7. A method forfabricating a semiconductor device according to claim 5, wherein saidsemiconductor device is used for a display device selected from thegroup consisting of a video camera, a digital camera, a goggle-typedisplay, a navigation system, a sound reproduction device, a lap-toppersonal computer, a game machine, a portable information terminal, andan image reproduction device.
 8. A method for fabricating asemiconductor device comprising: forming a semiconductor film having anamorphous structure over a substrate; and irradiating the semiconductorfilm with a laser beam condensed into a linear shape in an oxygenatmosphere while floating the substrate and applying ultrasonicvibration to the substrate to crystallize the semiconductor film.
 9. Amethod for fabricating a semiconductor device according to claim 8,wherein said laser beam is a YVO₄, a YAG, a YLF or an excimer laser. 10.A method for fabricating a semiconductor device according to claim 8,wherein said semiconductor device is used for a display device selectedfrom the group consisting of a video camera, a digital camera, agoggle-type display, a navigation system, a sound reproduction device, alap-top personal computer, a game machine, a portable informationterminal, and an image reproduction device.
 11. A method for fabricatinga semiconductor device comprising: forming a semiconductor film havingan amorphous structure over a substrate; irradiating the semiconductorfilm with a laser beam condensed into a linear shape while applyingultrasonic vibration to the substrate to crystallize the semiconductorfilm; and crystallizing a whole surface of the semiconductor film whileoverlapping a beam spot of the laser beam on the film.
 12. A method forfabricating a semiconductor device according to claim 11, wherein saidlaser beam is a YVO₄, a YAG, a YLF or an excimer laser.
 13. A method forfabricating a semiconductor device according to claim 11, wherein saidsemiconductor device is used for a display device selected from thegroup consisting of a video camera, a digital camera, a goggle-typedisplay, a navigation system, a sound reproduction device, a lap-toppersonal computer, a game machine, a portable information terminal, andan image reproduction device.
 14. A method for fabricating asemiconductor device comprising: forming a semiconductor film having anamorphous structure over a substrate; crystallizing the semiconductorfilm having an amorphous structure by adding a metal element or a metalcompound having catalytic action for enhancing a crystallization of thesemiconductor film and by heat-treating; and irradiating thesemiconductor film with a laser beam condensed into a linear shape whilefloating the substrate and applying ultrasonic vibration to thesubstrate in order to improve a crystallinity of the semiconductor film.15. A method for fabricating a semiconductor device according to claim14, wherein said laser beam is a YVO₄, a YAG, a YLF or an excimer laser.16. A method for fabricating a semiconductor device according to claim14, wherein said semiconductor device is used for a display deviceselected from the group consisting of a video camera, a digital camera,a goggle-type display, a navigation system, a sound reproduction device,a lap-top personal computer, a game machine, a portable informationterminal, and an image reproduction device.
 17. A method for fabricatinga semiconductor device according to claim 14, wherein said metal elementis nickel or platinum.
 18. A method for fabricating a semiconductordevice comprising: forming a semiconductor film having an amorphousstructure over a substrate; crystallizing the semiconductor film havingthe amorphous structure by adding a metal element or a metal compoundhaving catalytic action for enhancing a crystallization of thesemiconductor film and by heat-treating; irradiating the semiconductorfilm with a laser beam condensed into a linear beam while applyingultrasonic vibration to the substrate in order to improve acrystallinity of the semiconductor film; and improving a crystallinityof the semiconductor film while overlapping a beam spot of the laserbeam on the film.
 19. A method for fabricating a semiconductor deviceaccording to claim 18, wherein said laser beam is a YVO₄, a YAG, a YLFor an excimer laser.
 20. A method for fabricating a semiconductor deviceaccording to claim 18, wherein said semiconductor device is used for adisplay device selected from the group consisting of a video camera, adigital camera, a goggle-type display, a navigation system, a soundreproduction device, a lap-top personal computer, a game machine, aportable information terminal, and an image reproduction device.
 21. Amethod for fabricating a semiconductor device according to claim 18,wherein said metal element is nickel or platinum.
 22. A laser processingapparatus comprising: a means for floating and transporting a substratein a horizontal direction; an optical system for condensing a laser beaminto a linear shape or a rectangular shape; and a means for applyingultrasonic vibration to the substrate.
 23. A laser processing apparatusaccording to claim 22, wherein said laser beam is a YVO₄, a YAG, a YLFor an excimer laser.
 24. A laser processing apparatus comprising: ameans for transporting a substrate in a horizontal direction by a meansfor holding its end portion and moving in one direction and a means forfloating the substrate; an optical system for condensing and irradiatingthe semiconductor film with a laser beam to the substrate; and a meansfor applying ultrasonic vibration to the substrate from a region forholding the substrate.
 25. A laser processing apparatus according toclaim 24, wherein said laser beam is a YVO₄, a YAG, a YLF or an excimerlaser.